NMR in pure3He films on a Nuclepore substrate

The properties of³He films on a Nuclepore substrate have been measured by pulsed NMR at a Larmor frequency of 10 MHz between 1.3 and 4.2 K. The³He film thickness was varied from 0.14 to 2 layers. The spin-spin relaxation timeT ₂ agrees well with previous measurements of³He films on Mylar and Vycor glass at low temperatures. The spin-lattice relaxation timeT ₁ for submonolayer films shows a strong temperature dependence consistent with a thermally activated process. This behavior has not previously been observed on amorphous substrates. The spin diffusion coefficient was measured for the thickest films at 4.2 and 2.6 K and found to be consistent with free atom motion of the³He in the vapor. In thin films or at low temperatures, the diffusion was too small to be observed. The magnetic coupling between the³He nuclei in a film and the protons in the Nuclepore substrate was determined from the effect of the³He on the proton-lattice relaxation time. It is about 100 times weaker than the interaction between³He and the fluorine nuclei in a Teflon substrate.     

Using a microstrip bandpass filter to compare different circuit analysis techniques

A 22.5-GHz microstrip bandpass filter is analyzed using three different circuit analysis techniques. Circuit theory modeling fails to provide an accurate prediction when compared to measured data. But a hybrid analysis, which uses electromagnetic field solver computations and circuit theory models, provides good agreement with measured data. A more complete field solver analysis of the filter also shows good agreement when compared to measurements. In the later two cases, the electromagnetic analysis captures the actual current distribution on the filter that circuit theory fails to predict. © 1995 John Wiley & Sons, Inc.     

PRACTICAL INCONSISTENCY MANAGEMENT FOR CRITICAL-TASKS DECISION-SUPPORT SYSTEMS

Abstract

In this paper, the problem of logical consistency in critical-tasks decision systems is addressed. It is shown how local search techniques can be used to check the (in)consistency of very large propositional knowledge bases (KBs). Using new heuristic findings. we can now implement efficient forms of diagnostic reasoning in the context of very large ICBs modeling deep models of complex devices and including patterns of default reasoning.     

An efficient solver for the RANS equations and a one-equation turbulence model

A three-stage Runge-Kutta (RK) scheme with multigrid and an implicit preconditioner has been shown to be an effective solver for the fluid dynamic equations. Using the algebraic turbulence model of Baldwin and Lomax, this scheme has been used to solve the compressible Reynolds-averaged Navier–Stokes (RANS) equations for transonic and low-speed flows. In this paper we focus on the convergence of the RK/Implicit scheme when the effects of turbulence are represented by the one-equation model of Spalart and Allmaras. With the present scheme the RANS equations and the partial differential equation of the turbulence model are solved in a loosely coupled manner. This approach allows the convergence behavior of each system to be examined. Point symmetric Gauss-Seidel supplemented with local line relaxation is used to approximate the inverse of the implicit operator of the RANS solver. To solve the turbulence equation we consider three alternative methods: diagonally dominant alternating direction implicit (DDADI), symmetric line Gauss-Seidel (SLGS), and a two-stage RK scheme with implicit preconditioning. Computational results are presented for airfoil flows, and comparisons are made with experimental data. We demonstrate that the two-dimensional RANS equations and a transport-type equation for turbulence modeling can be efficiently solved with an indirectly coupled algorithm that uses RK/Implicit schemes.     

基于重力坝三维设计的CAD动态交互系统开发

为了在可研阶段合理、快速地制定重力坝设计方案,减少设计周期和成本,采用极限状态设计的方法,利用VB 6.0可视化编程工具开发出了一套能够与CAD动态交互的重力坝三维设计系统。该系统通过对Auto-CAD的二次开发实现了重力坝的三维参数化建模,并对所建三维模型进行结构计算,将设计与计算紧密结合,通过动态交互简化了大量复杂数据的计算,达到精确、快速完成断面设计的目的。经实践检验证明,该系统大大提高了断面设计效率,实用性强,对可研阶段的方案比选具有重大意义。     

SETTING INTERNAL AUDIT’S LONG-TERM PRIORITIES

As I have discussed in past articles, internal audit efforts must be risk-based and contribute to the long-term assurance needs of the organization and its board. A formal risk-assessment audit must be completed at least annually and the results of that assessment should direct audit priorities. Periodic updates throughout the year are also highly recommended. Over time, a focus on short-term results (quarterly financial results, meeting current regulatory requirements, etc.) has driven the priorities of management and consequently the organization toward a short-term perspective. Similarly, internal auditing’s efforts has commonly moved toward this short-term focus, boiling down priorities to whichever audits the company needs to complete in the immediate quarter or two. During the challenging business environment period some would say it is not a good time to refocus sights on the long-term horizon. I disagree. For example, knowing what the organization want to achieve in the next two to five years, and what does it need to do to get there, is critical to success! Certainly, each organization will have different goals, objectives, issues, and challenges, and no single “standard” long-term internal audit plan will work; but I took a shot at it anyway, and present the results in this article.     

圆锯片综合特性检测系统的硬件设计

圆锯片综合特性检测系统是根据国内外学者的圆锯片适张研究成果和频谱分析、坐标映射的理论,综合计算机技术、传感器技术、信号调理技术和数据采集处理技术来开发的,检测系统软件是Visual C 开发,在Win32环境下运行.整个检测系统操作简便、人机界面友好、具有较强数据管理功能,能在工业现场条件下快速、准确、无损地检测圆锯片适张状态.     

Stability of interests and the predictive and concurrent validity of the 1981 Strong-Campbell Interest Inventory for college majors.

116 of the 162 Occupational scales of the 1981 revision of the Strong-Campbell Interest Inventory (SCII) were constructed with new criterion samples. This study (a) assessed the concurrent and predictive validity of the revised SCII and explored its usefulness for predicting college majors (Exp I) and (b) examined the differential effect of stable and unstable interests during college on the validity of the SCII (Exp II). Data were analyzed for 354 females and 261 males who completed the SCII as college freshmen; 81% were still enrolled in school at the time of this study. Results indicate that the revised SCII can be used to predict college majors, having concurrent and predictive validity comparable to previous forms of the SCII. It was slightly more predictive for females than for males. Findings also show that the majority of Ss had stable interests during their college careers. The revised SCII was significantly more predictive of college majors for Ss who were satisfied with their majors or who had stable interests than it was for those who were dissatisfied or had unstable interests. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)